Check for picking mechanism



Nov. 20, 1956 e. w. PEARCE 2,771,099

CHECK FOR PICKING MECHANISM Filed July 20, 1954 3O 4 5 6 FIG. I 2\ WWII: #14

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. INVENTOR 66 GEORGE w. PEARCE J1? 6M Tw ATTORNEY CHECK FoR PICKING MECHANISM George W. Pearce, Danvers, Mass, assignor to Crompton & Knowles Loom Works, Worcester, Mass, a corporation of Massachusetts Application July 20, 1954, Serial No. 444,502

13 Claims. (Cl. 139-147) This invention relates to improvements in checking means for the shuttle picking mechanism of looms and it is the general object of the invention to provide improved means for absorbing energy remaining in the moving parts of the picking mechanism after the shuttle propelling operation is completed.

Certain types of picking mechanism utilize a shaft which is rocked by cam action and is connected to the picker stick by means of a sweep stick or the like. At the end of a picking stroke of the stick the shaft is moving at a high rate of speed and its momentum is likely to be transferred by means of the sweep stick and lug strap to the picker stick, thus subjecting the latter to excess strain after it has completed its work. The result of this strain is likely to cause breakage of the stick, this breakage being due not to stresses incident to picking the shuttle but to arresting the picking shaft and parts associated with it after the picking stroke has been completed.

Many of the devices proposed heretofore to arrest the momentum of the picking shaft include springs which have an objectionable rebound action. It is an important object of the present invention to provide a checking means effective to arrest motion of thepicking shaft either near or at the end of the working stroke of the picker stick by resilient means so constructed as not to cause any objectionable rebound.

The resilient means already mentioned is preferably in the form of two sets of resilient rings, one set within the other, the rings of the outer set having internal concave conical surfaces to engage external convex conical surfaces on the rings of the inner set. The force to be checked is exerted against these rings in the direction of their axes and the relative moment of the conical surfaces of the two types of rings causes compression of the inner set of rings and expansion of the outer set. The deformation of the rings is in planes at right angles to the ring axes with the result that there is little if any tendency to cause the rebound ordinarily found with the usual type of spring.

In order that still further reduction of rebound may be effected it is a further object of the invention to transmit the force to be absorbed to the aforesaid rings by two members which have coacting surfaces effective to change the direction of transmission of force from the picking shaft to the rings. This result is attained by primary and secondary plungers, the first of which receives a direct force from the picking shaft and the other of which is moved by the firs-t plunger and exerts force against the rings.

It is a still further object of the invention to provide a shock absorbing unit containing the aforesaid rings and plungers and provided with means for adjusting a preset stress on the rings so that the force exerted by the checking mechanism can be varied.

' In order that the invention may be clearly understood vention and in which:

Fig. l is a front elevation of the lower part of one end of a loom having the invention applied thereto,

Fig. 2 is an enlarged view of part of the structure shown in Fig. 1,

Fig. 3 'is a top view looking diagonally in the direction of arrow 3, Fig. 2, showing the upper part of the checking mechanism,

Fig. 4 is a section on line P4, Fig. 2,

Fig. 5 is an enlarged vertical section on line 5-5, Fig. 4,

Fig. 6 is a horizontal section on line 6-6, Fig. 5,

Fig. 7 is an enlarged detail vertical section on line 7-7, Fig. 5, and

Figs. 8, 9 and 10 are diagrammatic views illustrating the manner of operation of the invention.

Referring particularly to Fig. 1, part of the loom frame is shown at 1 and part of the lay is shown at 2, this part being supported on one of the layswords shown at 6. The lay has a shuttle box 4 provided in the present instance With a picker spindle 5 along which slides a shuttle picker 6. The picker is actuated by a picker stick 7 the lower end of which is pivoted at 8 to the usual rocker iron 9 secured to a rocker shaft 10.

The loom has top and bottom shafts 1'1 and 12 respectively, which are connected together by gears 13 and 14, respectively, so that the bottom shaft rotates once for every second rotation of the top shaft, although this ratio is not essential to the operation of the invention. Secured to the bottom shaft is a picking arm 15 having a picking roll 16 rotatably mounted thereon for engagement with a cam 17 secured to a picking shaft 18 which is suitably mounted for rocking movement in the loom and extends back and forth therein in usual manner. The picking shaft has secured thereto a power arm 20 the upper end of which is connected at 21 to a sweep stick 22 the outer end of which is provided by a lug strap 23 which surrounds the picker stick in usual manner.

In the particular loom shown in Fig. 1 the loom frame has a brace 25 which extends backwardly and forwardly and is connected to the front cross girt 26. A return spring 28 of the usual type may be attached to the lower end of the picker stick to return the latter to the outward position shown in Fig. 1 against a picker stick check 2s. The latter need not necessarily be used, or can be replaced with any other approved form of picker stick check to resist outward movement of the picker stick, to the right in Fig. 1. The spindle 5 may be surrounded by a buffer 30 to check the inward motion of the picker 6 at or near the end of the working stroke of the picker stick.

The matter thus far described is of usual construction and operates in the ordinary manner. Rotation of shaft 12 causes the picking roll 16 to engage the cam 17 to rock the shaft 18 in a counter-clockwise direction as viewed in Fig. 1 whenever a shuttle is to be picked from the right-hand side of the loom, this being the side shown in Fig. 1. During continued engagement of the roll with the cam the rate of turning of picker shaft increases in order to give acceleration to the picker stick, and when the picking stroke is completed the picking shaft and the parts connected to it, such as the cam and the arm 20, have stored in them considerable energy which should be checked promptly in order to prevent too great a strain from being transmitted through the sweep stick and lug strap to the picker stick. Unless the momentum of the picker shaft is promptly checked there is likelihood that its overtravel after completion of the picking stroke will result in breakage of the picker stick. It is the general object of the present invention to provide simplified and improved means for absorbing the energy of the rotating shaft and the parts connected to it so that the picker stick will not be subjected to the forces incident to arresting rocking motion of the picker shaft upon completion of the picking stroke.

In carrying the invention into effect the power arm 20 is provided with a thrust foot 35 having a face 36 which is preferably flat and is on the leading side of the power arm 20 during a picking stroke. The checking mechanism comprises a stationary support in the form of a hollow body or casting 40 having a primary bore or channel 41 which may be rectangular in cross section and having also a secondary bore or channel 42 transverse of the first channel, preferably at right angles thereto as shown for instance in Fig. 5. The bottom of channel 41 is provided by a plate 43 which forms part of the support structure of the check mechanism as will be described hereinafter.

Slidable in the primary bore 41 is a primary plunger 45 having an enlarged head 46 to fit the channel 41 and having a reduced end 47 to fit a reduced extension 48 of the channel 41. Two hunters 50, made preferably of some suitable shock absorbing material such as nylon, are set into the head 46 of the primary plunger as shown in Figs. 5 and 6. These hunters may be driven into holes 51 in the head and are so placed as to be engaged by the thrust foot 35. The primary plunger is provided with an inclined face 52 which tapers downwardly in a direction away from the hunters as shown for instance in Fig. 5. In order to limit motion of the primary plunger to the left as viewed in Fig. 5 the reduced part 47 thereof is provided with two stop means 55 each including a screw 56 tapped into the primary plunger and a washer 57 of sufiicient size to engage stationary parts of the check structure, such as the casting 40 and the plate 43.

A secondary plunger 60 is slidable in the secondary bore 42 and has an inclined face 61 in engagement with the face 52. The plunger 60 has an upper flat face 62 above which is arranged a nest of resilient elements shown here as ring springs designated generally at 8. These ring springs are of two types arranged in two sets, one inner and the other outer. The ring elements of the outer set are shown at 65 and have cylindrical outer surfaces 66 to slide along the bore 42. The rings 65 have inner concave conical surfaces 67 and 68 located respectively at the right and left as viewed for instance in Fig. 9. Normally these ring springs 65 will be separated from each other by spaces designated at 69.

The ring springs of the inner set are designated at 75 and have outer right and left convex conical surfaces 76 and 77 respectively, which engage corresponding concave conical surfaces of the adjacent outer spring members 65. These inner ring members are also separated under normal conditions by spaces 78. The diameter of the bore 42 is somewhat larger than the outside cylindrical diameter of the ring springs 65 to permit the latter to expand slightly during the checking operation.

The upper end of the body or casting 40 is provided with a stop plug 85 having screw threads 86 which are tapped into screw threads 87 in the upper end of bore 42. The lower end 88 of the stop 85 is cylindrical and terminates in a fiat bottom surface 89. The upper part of the body 40'is split as at 90 and a bolt 91 passing through the split part can be tightened to clamp the stop plug 85 in adjusted position.

As shown in Fig. 7 the uppermost inner ring 75a is of. half the width of the other inner ring members 75 and, is in engagement with the bottom surface 89 of the stop 85. In similar manner the lowest inner ring spring 65a is of half the width of the other inner rings and engages the upper surface 62 of the secondary plunger. The plate 43, the hollow body 40, and the parts in the body comprise a checking unit U.

Under normal conditions the springs will he in their normal form, or will be under a slight pre-set stress due to downward adjustment of stop 85, and force derived from the preset condition of the rings will be transmitted by the secondary plunger through surfaces 61 and 52 to 4. hold the primary plunger in its normal position as viewed in Fig. 5.

Near the end of the working stroke the thrust foot 35 will engage the hunters 50 and move the primary plunger to the right as viewed in Fig. 5 the effect of which would be to elevate the secondary plunger due to coaction of the inclined and mutually engaging surfaces 52 and 61. As the secondary plunger rises the conical surfaces of the ring elements will coact to cause compression of the inner ring elements and expansion of the outer ring elements, and the resistance of the elements to this deformation will oppose upward motion of plunger 60. The play between the outer ring elements and the bore 42 already alluded to will permit expansion to the outer ring elements. As the secondary plunger continues to rise the rings will move from the positions shown in Fig. 9 toward the positions shown in Fig. 10. The end to end engagement of the rings shown in Fig. 10 may not result in every instance, but as the rings approach the position shown in that figure they will offer increasing resistance to upward motion of the secondary plunger. In Fig. 10 it is assumed that the'expansion of the outer rings will be sufficient to cause the cylindrical surface 66 to he in engagement with the bore 42, although this engagement is not essential.

It is found that a checking mechanism made as described operates efiectively to stop the motion of the picker shaft by a comparatively small endwise motion of the primary plunger 45. The ring springs tend to recover their normal form and in doing so reestablish'the relation shown for instance in Fig. 9, but this recovery is not accompanied by an abrupt rebound action, and this is due in part to the fact that the resetting force is transmittedthrough surfaces 52 and 61.

The time of engagement of the thrust foot with the hunters 50 with respect to the time of disengagement of the roll 16' of the cam 17 may be varied as desired. In one setting of the invention which has operated satisfactorily the cam is permitted to have a full motion imparted to it by the roll 16 before the thrust foot engages the hunters 50, but in another setting which has been satisfactory the partsare set so that the thrust foot engages the bunter during the latter part of the engagement of the roll with the cam. In either instance it is desirable that the energy'of the picker shaft be absorbed before motion of the upper end of the picker stick is checked'by the hunter 30, whether the latter be of the form specifically shown in Fig. 1, or in any of the other well-known forms.

The details of, mounting the check mechanism are shown more specifically in Figs. 1 to 4. A stand 95i's secured to the girt 26 by bolts 96 and is attached by bolts 97 to the forward partof a support base 98 of which the previously mentioned plate 43 is a part. The rear part of support 93'has a vertical part 99 bolted at to a short girt 1111 bolted at 102 to previously described brace 25. secure the casting 40 to the plate 43. Anyother convenient means for mounting the check mechanism may be employed other than that shown specifically therein, but it is desirable that the check unit be capable of ad justment toward and from the shaft 18. This adjustment is provided for by slots 1115 in girt 26 for bolts 96 and slots 1136 in support 98-for bolts 100. The stand 95 may be provided with a'rib 167 to engage that part of the support 93 facing away from the shaft 18 inorder to hold the-check against displacement from its adjusted position.

It is found that lubrieationis important in order to attain satisfactory results in the operation of the check mechanism. A lubricant, such a a-mixture of graphite and oil, can he used each of the nu s bein lubricated before being put in place, and subsequent lubrication being effected through the upper end of the bore 42 after the stop 85 has been removed;

From the foregoing it will be seen that the invention Screws 163, see Figs. 4 and 5,

sets forth an eflfective check for the picking mechanism of a loom wherein the residual energy stored in the picking shaft and the parts connected to it upon completion of the picking stroke is absorbed by causing compression and expansion of inner and outer sets of spring rings which may be considered as compression and tension members, the deformation of the rings being in planes at right angles to their axes and due to motion along their axes and the coaction of the conical engaging surfaces on the two sets of rings. This arrangement results in very little rebound at the end of the checking operation. The checking unit U includes a primary plunger which receives the force to be checked and a secondary plunger at an angle to it which acts to deform the ring springs in the secondary bore between the stop and the secondary plunger. More generally, however, the rings are operatively connected to the plunger 45 and the plunger 60 may not be necessary in all forms of the invention. The surfaces 52 and 61 cause the force to be checked to turn its direction and this fact, due to friction of the surfaces, assists in absorbing the force. Also, the stop 85 serves as a means to confine the rings springs in the bore 42 and also to give them a pre-set stress which will make them immediately effective as soon as the primary plunger is moved by the thrust foot 35. The inclined and mutually engaging conical surfaces of the ring spring elements serve due to the inherent resilience of the rings to restore the parts to the position shown in Fig. 5 after the checking operation is completed. As an example of the angles involved in one form of the invention which has operated successfully it may be mentioned that the bores 41 and 42 were at right angles to each other and the surface 52 was at an angle of 26 /2 degrees to the direction of motion of the primary plunger. Also, the concave and the convex surfaces on the outer and inner rings were inclined about 14 degrees to the axes of the rings, but the invention is not limited to these angles.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In checking mechanism for a loom picking shaft having a thrust member moving therewith, stationary support means, a primary plunger slidable on said support means and positioned for engagement with and movement by the thrust member during a checking operation of the mechanism, a secondary plunger also slidable on said support means but in a direction transverse of the direction of sliding movement of the primary member, coacting surfaces on said plunger at least one of which is inclined to the direction of movement of the primary plunger, said coacting surfaces effective due to movement of the primary plunger by the thrust member to cause movement of the secondary plunger in a direction away from said primary plunger, and resilient means resisting movement of the secondary plunger away from said primary plunger, said resilient means comprising two sets of coacting rings, the rings for one set being subjected to a force tending to expand them and the rings of the other set being subjected to a force tending to compress them when the secondary plunger has said movement in a direction away from the primary plunger.

2. The checking means set forth in claim 1 wherein the support means is a hollow structure in which the plungers are slidable and within which the sets of rings are confined in the path of movement of the secondary plunger.

3. The checking mechanism set forth in claim 1 wherein the support means has a guide bore along which the secondary plunger moves and the sets of rings are located in said bore on the side of the secondary plunger opposite to the primary plunger.

4. The checking means set forth in claim 1 wherein the coacting surfaces on said plungers are both inclined to the direction of movement of the primary plunger.

5. The checking mechanism set forth in claim 1 wherein stop means limits movement of the primary plunger in a direction opposite to the movement imparted thereto by said thrust member and said sets of rings cooperate with said stop and act by a force transmitted through said coacting surfaces to hold the primary plunger in normal position in readiness for movement by said thrust member.

6. In checking mechanism set forth in claim 1 wherein said set of rings during the checking operation are subjected to deformation forces acting in planes substantially at right angles to the direction of movement of the secondary plunger.

7. The checking mechanism set forth in claim 1 wherein the support means has a bore in which the secondary plunger slides and the two sets of coacting rings are confined within said bore.

8. The checking mechanism set forth in claim 7 wherein one of said sets of rings is within the other set and has convex conical surfaces to engage concave conical surfaces on the other set.

9. The checking mechanism set forth in claim 7 wherein said rings of each set are normally spaced from each other prior to operation of the checking mechanism and are moved toward each other during operation of the checking mechanism.

10. The checking mechanism set forth in claim 7 wherein an adjustable stop in the bore limits movement of said rings within the bore lengthwise of the latter by the secondary plunger.

11. The checking mechanism set forth in claim 7 wherein said rings are confined between said secondary plunger and an adjustable stop in the bore.

12. The checking mechanism set forth in claim 11 wherein said adjustable stop presets said rings to place them under a normal small degree of deformations.

13. In checking mechanism for a loom picking shaft having a thrust member moving therewith, stationary support means, a plunger slidable on said support means and normally positioned for engagement with and movement by the thrust member in a given direction during a checking operation of the mechanism, two sets of coacting tension and compression members mounted on the support means and operatively connected to the plunger, the members of one set being subjected to a force tending to expand them and the members of the other set being subjected to a force tending to compress them when the plunger has said movement in said given direction to check said thrust member, said members of one set contracting and the members of the other set expanding after said thrust member has been checked and the members of the two sets cooperating to move the plunger in a direction opposite to said given direction back to the normal position thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,153,531 Adams Sept. 14, 1915 2,429,140 Snyder Oct. 14, 1947 2,484,119 Rinne Oct. 11, 1949 2,621,680 Vincent et al. Dec. 16, 1952 2,692,661 Bertsch et al. Oct. 26, 1954 

